Purpose to determine the efficacy and safety of heme arginate for the treatment of the acute porphyrias. Specific aims are 1) to determine in 20 patients with acute attacks of porphyria whether heme arginate is safe and effective in producing remissions of symptoms and lowering porphyrin precursors; 2) doseranging studies of effects of heme arginate on reducing porphyrin precursor levels in 16 stable patients with acute intermittent porphyria; and 3) to study the value of heme arginate infusions for prevention of attacks of porphyria in 15 patients.